An implantable cardiac stimulus device (ICSD) typically senses cardiac electrical signals in an implantee and uses the sensed signals to classify the implantee's cardiac rhythm as normal/benign or malignant/treatable. Illustrative malignant arrhythmias may include ventricular fibrillation and/or ventricular tachyarrhythmia. Other conditions including non-ventricular arrhythmias may also be considered “treatable” depending upon patient characteristics and physician preferences.
A method of analyzing cardiac signal data may begin by detecting cardiac events in sensed signals. However, signals sensed by implantable cardiac systems can be subjected to many sources of noise, where noise, for a cardiac system, is defined as any non-cardiac signal. Differentiating noise from likely cardiac events can be a challenging task for the implantable device.
New or alternative methods for ensuring accurate cardiac event detection are desired.